Method of subjecting lacquered leather and the like to the light treatment.



A. JUN GHANS.

METHOD OF SUBJEOTING LACQUERED LEATHER AND THE LIKE TO THE LIGHT TREATMENT.

APPLICATION FILED FEB.24, 1912.

1,099,378, Patented June 9,1914.

UNITED STA S PATENT OFFICE.

ARTHUR JUNGHANS, OF SCHRAMBERG, GERMANY.

METHOD OF SUBJECTING LACQUERED LEATHER"AND THE LIKE TO THE LIGHT TREATMENT.

Specification of Letters Patent.

Patented June 9, 1914.

Application filed February 24, 1912. Serial No. 679,777.

To all whom it may concern:

Be it known that I, ARTHUR JUNGHANS, royal privy commercial councilor, subject of the King of Wurttemberg, residing at Schramberg, VVurttemberg, Germany, have invented certain new and useful Improvements in Methods of'Subjecting Lacquered Leather and the like to the Light Treatment, of which the following is a specification.

This invention relates to the treatment of lacquered leathers, which for the purpose of receiving a suitable covering layer of lacquer are subjected to an artificial light ex JOSIIIQ.

acquered leathers, on whose layers of lacquer great demands are put during manufacture and subsequent use, must be frequently subjected to a light exposure after the drying process for the purpose of attaining the desiredproperties. This light exposure has especially for its object to produce suchhardeningof the surface of the layer of lacquer that the piled skins do not stick together and dirt and dust do not adhere to the layer of lacquer but that this layer remains flexible in order that when manufacturing and using the articles made of the leather, a cracking of the layer is prevented as far as possible. The treatment Was hitherto carried out in that the skins stretched on frames or nailed on boards were directly exposed to the sunlight and remained exposed to this light until a thorough hardening to the required extent Was attained. Now attempts have been made to replace the sunlight exposure by artificial light exposure in order to render the manufacture of lacquered leather independent of the existing weather conditions. A satisfactory result could however not be obtained with the light sources hitherto employed (electric incandescent lamps and electric are light) for in the case of ex osure by means of incandescent lam s, thee ect attained thereby was quite insu cient or inthe case of are light, the costs incurred were in no proportion to the result obtained, thus an economical carrying out of the process for industrial purposes was absolutely impossible.

The present invention-is also based on the employment of artificial light sources but aims at an exposureby means of a special selected light, which first insures an intensive effect and also permits an economical operation excluding the disadvantage hitherto present.

During his investigations and experiments, the inventor has found out that they are chiefly ultra violet rays which durmg the exposure exert a very favorable influence on the drying and hardening process while the other rays also contained in the light give detrimental accessory efi'ects. Consequently, the new method resides in carrying out the light exposure by means of such light sources, whoselight is rich in ultra-violet rays and therefore poorer in other rays which under certain circumstances have, a detrimental effect. In this respect, the so-called mercury vapor lamps chiefly come into consideration which em-. body this abundance of ultra-violet rays in a special degree. The best effect is however attained by those mercury vapor lamps, whose arcs are inclosed in the quartz pervious to rays of a short wave length, while the light sources produced by high tension discharges, which are also very rich in ultraviolet (short wave length) rays are only of secondary moment. They can however always be advantageously used but do not yield at first such high results as the aforesaid mercury vapor lamps with arc inclosed in quartz or so-called quartz lamps.

Exhaustive experiments, which applicant has carried on with quartz-lamp light sources in connection with the use of ultraviolet rays as a drying and hardening medium for lacquered leather, show that by this light drying process certain accessory reactions occur outside of those reactions which are desired, these accessory reactions having a detrimental influence on the hardening process. A great number of experiments disclosed ultimately that it is the ozone which is generated in considerable quantity by the ultra-violet rays which acts so harmfully. If the ozone is removed, as by means of liberal artificial ventilation of the drying chamber, then the undesirable accessory reactions of the short waved rays also disappear. This became evident from the following experiments: \Vith other conditions similar lacquered leather was once treated with light with simultaneous ventilation, and at another time without the simultaneous ventilation. The leather dried good for an extendedperiod in storage;

while that treated according to the second process became sticky after a very short time. By repetitions of theseexperiments at difi'erent times, it was clearly shown also, that by the first process differences with re'-' spect to the. tendency of the longer stored leathers to stick together were noticeable. A thoroughexamination of the conditions under which the experiments took place, disclosed finally that the desirable action of ventilation abated under higher temperatures. From that it is evident that for the production of a complete drying, not only ventilation, but a regulation of temperature was necessary. A closer study showed that the ozone formed at higher temperatures reacted-materially more energetically-and became therefore particularly harmful. The process is therefore most successfully carried out when the temperature is low. Since, on the other hand, the production of very cold bodies of air is too expensive, this being particularly true in summer, certain other experiments were carried out in order to find out just how high it was possible to carry the temperature with good results. It was established that the undesirable action of ozone is not so strong at temperatures approaching as high as 25 C. that it was dangerous to the.exposed leather. Obviously no sharply defineddivision line exists on one side of which it is impossible to produce good lacquered leather. It is possible for example to secure a leather-at 30 C. which, stored in winter in a dry room, 'i'jwill hold-its properties for several months.

Should it be necessary to make a 'prodnot which will wear without injury under adverse conditions, as in tropical climates or on long sea voyages, then it is absolutely necessary to operate at the lowest possible temperature. This fact brings'to light that there is a lower limit which is established by the fact that lacquered leather becomes brittle and easily destroyed at very low temperatures, as, for example, at such temperatures as lie below the freezing point." It is most practicable to carry out the process in chambers which are so ventilated that the air therein can be renewed in about every two minutes and the temperature of this a1r can be maintained at temperatures lying between 10 and 25 C. For the purpose of practically carrying out the new "method, it has meanwhile been deemed the best course to efiect the exposure inxbox-like .closed rooms or spaces, which are provided with suitable means for ventilation and for regulating the tem erature. For example, in

one case, bullo s hides, which were black lacquered and from one series of manufacture, were subjected to-a comparative test,

new method. A part of these hideswas exposed'to thesunlight and an exposure of at was necessary for'attaining the desired degree of hardness. Another part of these hides was subjected to the rays of ordinary electric incandescent lamp light and no practicable hardness was attained notwithstanding an exposure of several hours. a

third part of the hides was treated according to the described method and exposed to the rays of quartz lamps, the temperature being maintained at about 15 C. by special regulating means, ventilating means being also employed. An exposure of about 1 hour was quite suflicient for hardening the lacquered layers on the skins. The hardening also proved absolutely satisfactory, because it was neither too brittle nor too soft. The current supply 'of the quartz lamps was incandescent lamps which proved the double economy of the method (also absolutely and comparatively less current supply in consequence of shorter exposure and less current su ply of the light sources).

11 the accompanying drawings, which illustrate one form of apparatus which may advantageously be used to carry out the partly in section, of the drying chamber, and Big. 2 is an elevation, partly sectional, on the line a-a of Fig: 1.

Referring more particularly to said drawings, l'indicates, in general, the comparativel long, narrow housing or chamber in whic the leather is hung, or through which ultra-violet rays The leather is suitably stretched on forms or boards, (not shown), provided with rollers which run on the overhead tracks 2 and 3, arranged in parallel relation along the length of the chamber 1. Said tracks are suspended from doors or traps 5 and 6. The leather on t e forms is passed into the chamber at one end, as at a, and is removed at the opposite end,

as much as possible by removing the leather which has been exposed the longest, and movin the remaining forms along to make room or other sections of leather. Between the two tracks and dis osed in suitable relation thereto are sets 0 steam pipes 7, which are used to heat the leather in the preliminary step of the treatment. Midway of the length of the structure is suspended a lamp support '8, in the form of a beam, suspending rods 9 bein utilized. The-lamps 10 are carried by cords of varying lengths so distributed as to cause the light from the lamps least? hours with rather intensive sunlight,

present invention, Figure 1 is. plan view,

brackets 4, suitably secured to the walls of the housing, and access to said tracks is gained at each end of the chamber throu h as at b, so that the process can be expedited only a fraction of the'current supply of the it is passed, and exposed to the action of the to be evenly thrown over the surfaces of the sections of leather.

' branches, one extendlng over each half of the housing, and havin an inlet12 from said housing at a point w ich is substantially central to the half of the housing over which the branch is built. The two branches of the duct 11 enter a main duct 13 at their juncture, in which is located a fan 14, the latter serving to create a current of air through the housing, upwardly through the ducts 11 and out through the main duct 13. Besides the inlet and exit doors and 6 which give access to the housing 1, the latter is rovided with ventilating doors 15 in the si es thereof, for the purpose of properly regulating the drafts and temperature. By this system of ventilation, the ozone created in the chamber 1 is readily removed without disturbing. the drying action, and furthermore, the temperature may be regulated when the preliminary heating step is being carried out and simultaneously with the withdrawal of the ozone from the chamber. The .further operation of the apparatus is obvious from the description thereof, and need notbe particularly set forth.

I claim 1. A method of treating lacquered leather, consisting in exposing the same to light rich in ultra-violet rays, preventing the formationof ozone as far as possible by regulation of temperature, and disposing of the formed ozone by a simultaneous ventilation and regulation of temperature, substantially as described and for the purpose set forth.

2. A method of treating lacquered leather, consisting in exposing the same to light rich in ultra-violet rays, preventing the formation of ozone as far as possible by regulation of temperature, and disposingof the formed ozone by ventilation, substantially as described and for the purpose set forth.

3. A method of treating lacquered leather, consisting in exposing the same to art ficial light rich in ultra-violet rays, and disposing of the ozone which is formed, by a s1- multaneous ventilation and regulation of temperature, substantially as described and for the purpose set forth.

In testimony whereof I have afiixed my signature in presence of two witnesses.

DR. ING. ARTHUR J UNGHANS.

Witnesses Emens'r ENTENMANN, Fmoa Knnmnn. 

